AP Cliffs Bio. QUESTION

[heatwheat]

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#11 in the chapter "Cell Division" the question says,

"In typical cell divisions by mitosis and meiosis, all the following contribute to genetic variation EXCEPT:"
A. anaphase of mitosis
B. anaphase of meiosis I
C. fertilization
D. crossing over
E. random union of egg and sperm

The answer is A and I understand why, but why does fertilization contribute to genetic variation? I know that fertilization is random... but does the actual act of fertilization really contribute to genetic variation?

 

[211183]

Yes, you have a random sperm then meeting with the egg = genetic variation. It depends on what sperm it gets which, like you said, is random. Sexual reproduction = genetic variation. Compare it to asexual.. varies by mutations. Fertilization is combining two different sets of genes.

n+n = 2n ... = more possibilities

 

[klpennin]

Or you can think of it this way... if there was no genetic variation in the fertilization process.... all your brothers and sisters would look alike. random = genetic variation.

 

[doc3232]

I think what you should be asking is what is the difference between C and E.

 

[TheWiredNerv]

Think more broadly. Sorry to sound dirty but who you have sex with and fertilize adds to variation as there are many people to have sex with and the result is genetic variation. Also, like above posters said, each sperm may be different genetically.